Resilient lighting fixture hanger

ABSTRACT

A lighting fixture hanger for isolating a lighting fixture depending therefrom from vibration, the hanger including a cushion displaying variable rate spring characteristics. In a preferred embodiment, the hanger incorporates a conical spring which can easily and quickly be captivatively assembled into a subassembly forming the essential functional portions of the hanger.

United States Patent [72] Inventor Arthur ll. Appleton c/o AppletonElectric Co., 1701 W. Willington, Chicago, lll. 60657 [2l] Appl. No.809,525 [22] Filed Mar. 24, 1969 [45] Patented Nov. 16, 1971 [54]RESIILIENT LIGHTING FIXTURE MANGER 5 Claims, 6 Drawing Figs. [52] U.S.Cl 24U/90, 240/71, 240/67, 240/149, 240/85 [5l] lnt.Cl F21v15/04 [50]Field ot Search 240/90, 67, 71, 149 [56] References Cited UNITED STATESPATENTS 706,545 8/1902 Fleming 240/90 947,550 1/19 10 Ramsey 240/901,521,826 H1925 Mole et al.. 240/90 1,626,108 4/1927 Bommel 240/901,802,589 4/1931 Thompson 240/90 Primary Examiner-Samuel S. MatthewsAssistant Examiner-D. J. Clement Attorney-Jon l.. Liljequist BACKGROUNDOF THE INVENTION It is generally well known that light bulbs and lampswhich are subjected to vibration experience a shorter life than thosewhich are not so subjected. Thus, where lights are mounted in locationswhere there is a continuous vibration, such as in a factory containingheavy equipment which moves about or vibrates, the light fixtures arefrequently mounted with a shock-absorbing cushion interposed between thefixture and the ceiling or other like support. This is to prevent thevibration which is transmitted from the machines to the structure frombeing transmitted from the structure to the fixture. Fixture hangersalso usually incorporate some form of swivel mechanism to permit thefixture to hang vertically and assist the vibration isolation affordedby the cushion. By installing such a device in a vibrating environment,bulb or lamp life is increased beyond what it would be without thedevice. As a result, maintenance and material costs are conserved over along period ofoperation.

With the large variation in the size of lighting fixtures, manufacturersof fixture hangers who wish to have a hanger available 4for everyavailable fixture must produce and have available a wide variety ofsizes.

For example, Appleton Electric Company of Chicago formerly produced fourhangers of different capacity to handle different size fixtures; onebeing rated for use with fixtures weighing between 3 and 6 pounds,another for use with fixtures weighing between 6 and l2 pounds, a thirdfor use with fixtures ranging from `12 to 24 pounds, and the heaviestbeing suitable for use with fixtures ranging from 24 to 48 pounds.Eachof these basic units was produced in a variety of options to providefor the specific size of conduit interposed between the hanger and thelight fixture, and also to provide for the particular type of outlet boxto which it was attached. Thus, with only four basic weight ranges,which means four basic units, the various modifications called for bypurchasers might generate to 40 different models which must be carriedin stock and listed separately in the manufacturers catalog.

SUMMARY OF THE INVENTION lIn'its preferred form, the invention is madeup of four basic elements. These elements consist of a housing which isswivelly connected to an electric outlet box, a central stem piece towhich the fixture is attached by means of a length of conduit, vibrationisolation means in the form of a conical spring, having a nonlinearspring rate, and a washer. These four elements not only create aparticularly simple construction, but as will be described in greaterdetail hereinbelow, the spring permits a fewer number of basic units orweight ranges to cover the same total weight range of availablefixtures. The net result is that there is a drastic reduction in thetotal number of fixture hanger variations which must be cataloged andinventoried.

ln assembling the hanger, the stem, spring and washer are designed toform a primary subassembly which screws together simply but which isquite difficult to disassemble. The shape of the conical springfacilitates this assembly, and thereby this particular spring shapeserves at least a dual purpose.

DESCRIPTION OF DRAWINGS FIG. l is a perspective view of a light fixturedepending from a fixture hanger which includes the principles of thepresent invention.

FIG. 2 is a perspective view of the fixture hanger with its variouscomponents axially separated, this view also including a standardelectrical outlet box to which the hanger can be mounted.

FIG. 3 is a side elevation, partially in cross section, of the fixturehanger assembly shown in FIG. 1 and 2.

FIG. 4 is a side view, partially in cross section, of the severalcomponents which form the major subassembly in an axially displaced andexploded configuration showing their relative positions just prior toassembly.

FIG. 5is a cross-sectional view of the upper internal end of the stempiece taken substantially along the lines 5-5 of FIG. 4.

FIG. 6 is a plan view of the washer.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,and initially with particular reference to FIG. 1, there is shown alight fixture l0 including a combination shade and reflector portion 11and a globe portion 12 which surrounds a bulb (not shown). The lightreceives current from an outlet box 13 which is connected into the rigidconduit system 14, this conduit being rigidly affixed to some solidstructure such as a ceiling. Outlet box 13 is provided with a coverplate 13A and a yoke type of socket mounting 13B (see also FIG. 2).

Between the outlet box I3 and the fixture 10 is a hanger assembly 15 anda length of conduit 16. Conduit I6 is of some desirable length such thatthe fixture 10 will be situated a convenient or proper distance from thefloor. Hanger assembly 15 is interposed between electrical box 12 andconduit 16 and forms a vibration-isolating mounting in series therewithfor the purpose of isolating shock and vibration in the electrical box13 from the fixture l0. As was mentioned earlier, bulb life generallydiminishes with increasing vibration, and it is thus desirable to soisolate bulbs where the structure carrying the lighting fixtures issubjected to vibrationA and shock.

Fixture hanger l5 consists of four major components; a housing 20, avariable rate cushion in the form of conical spring`21, a modifiedwasher or closure plate 22, and a central stem 23. i

Housing 20 has'a lower, frustoconical portion 25 opening and divergingdownwardly so as to resemble a bell, and it has an upper, hemisphericalportion 26 opening and diverging upwardly. These two portions are hollowand these hollows cornmunicate with one another at a reduced-diameterneck portion 27 so that wires can be threaded therethrough. With theexception of an antirotational tang or web 28 form ed therewith, thehousing has an axis of symmetry 29 such that crosssectional planes-cutperpendicular thereto would display an annular ring of material.Hemispherical portion 26 has a smoothly contoured lower surface similarto a portion of the ball in a ball and socket joint to provide a bearingsurface for a swivel mounting. In mounting a fixture hanger assembly,this upper portion 26 is removably entrapped within an outlet box,generally as seen in FIG. 1. The inner, lower end of the bellshapedlower portion 25 has a shoulder 30 cut or cast therein to provide a flatsurface for receiving the modified washer 22.

With the exception of a notch 3l in its outer peripheral edge and a pairof identical and parallel flats 32 defining a part of its central hole,washer 22 is of generally standard shape. Notch 31 fits within a singletab or projection (not shown) provided therefor on the shoulder 30 ofthe housing 15. When properly oriented angularly, the notch 3l slipsover the projection so that the washer 22 can fully and 30, and in thisposition the washer is vrestrained against rotational movement relativeto the housing 15. Also in this position the washer is restrainedagainst axial movement relative to the housing by a staking operationwhich deformably drives material under the lower surface of the washeras at 33.

Contained entirely within the lower [portion 25 of the housing is avibration isolation device in the: form of a variable rate cushion. Morespecifically, this variable rate cushion takes the form of a conicalspring having a lower and preferably ground end 35 resting on washer 22.

Having a relatively large diameter lower end 35, the spring 21 maintainsa solid footing on the washer 22, and the inward taper to the upper endnot only inherently provides a variable spring rate, but also permitsthe use ofa smaller flange on the stem piece 23 as well as aparticularly simple method of assembly, to be described in greaterdetail below.

flushly engage the shoulder Referring now to stem piece 23, this pieceincludes a central shaft portion 40 having a pair of parallel flats 41on opposite sides thereof which are spaced slightly closer together thanthe parallel flats 32 defining the central hole in the washer 22. Thus,when the upper end of stem piece 23 is inserted through washer 22, therecan only be a slight degree of relative rotation therebetween. The upperend 42 of the stem piece has a pair of diametrically opposed ears 43projecting laterally outwardly therefrom. When viewed in cross section(see FIG. 5), the shape of this end of the stern piece can be seen to besubstantially identical to the shape of the hole in washer 22, however,its size in cross section is slightly smaller so that the eared end ofthe stem piece can be inserted through the washer. Also, as can be seenby the dashed line in FIG. 4, the distance between the lateralextremities of the two ears is considerably less than the inner diameterof the lowermost coil of spring 2l. In fact, this dimension on the stempiece is roughly comparable to the inner diameter of perhaps the middlecoil of the spring 21.

The lowermost end of the stem piece is designed'to receive a piece ofconduit having external threads at its upper end. To this end, thislowermost end has an enlarged-diameter portion 45 which thereby forms ashoulder 46 which can serve as a seat for the washer 22. This enlargedportion 45 has connection means in the form of internal thread 47, andthis thread is sized to receive a standard finch pipe thread.Immediately below portion 45 is a further enlarged portion 50 having aplurality of parallel fiats arranged around its external peripherysimilar to a nut. Extending transversely through portion 50 is athreaded hole 51 for receiving a setscrew (not shown), and extendingentirely through the stem piece longitudinally is a passageway 52.

Thus, when it is desired to snugly secure a piece of conduit or conduitplus attached fixture to the lower end of the stem piece, the outersurface of lower portion 50 can be grasped with an ordinary wrench whilethe conduit is screwed up into threads 47. The setscrew can then bedriven into the conduit to prevent it from turning. In the event l/-inchconduit is used rather than the V4-inch conduit, a yi to l/-inch reduceris supplied with the hanger.

In assembling the fixture hanger, washer 22 is dropped over the upper oreared end 42 of the stem piece 23. The larger end of spring 21 isthensimilarly slipped thereover, but the proiecting ears 43 on the stempiece only permit the spring to slip about half way thereover beforeinterference results. However, by grasping pieces 21 and 23 and rotatingthem relative to vone another in the proper direction, the ears 42 screwthemselves up along the coils of diminishing diameter. Although theupper end 55 of the wire forming the spring is snugly nestled againstthe second coil as at 56, the ears 43 can reasonably effortlessly besnapped past this contact point 56 whereupon the spring 2l is totallyentrapped between the ears 42 and the washer 22 which rests on shoulder46. Although there is no reason for so doing, it will be appreciatedthat it would be considerably more difficult to remove the spring fromthe stem piece because the upper two coils would have to be separated bysome external means before the ears 42 could be slipped therebetween andreversibly rotated to disassemble the parts.

With the spring 21, washer 22, and stem piece 23 now forming aninterlocking subassembly, this subassembly is inserted up into the lowerbellshaped end portion 25 of the housing such that the washer 22 seatsflushly against the shoulder 30 therein. As will be recalled, this canonly occur when the notch 31 in the washer 22 bridges the projection(not shown) cast integrally with and onto the shoulder 30. When in thisposition, the lowermost end portions of the housing are stacked over thewasher at eight equally spaced locations around its periphery to lockthe washer in place. Upon attaching the setscrew and 341 to l/-inchreducer, the hanger is ready for shipment.

, In installing the hanger into an outlet box such as that shown at 13,the cover plate 13A is removed from the outlet box to expose a sideentrance to the socket 13B which matingly received the hemisphericalball end 26 of the housing 20. After inserting this end 26 into theelectrical box with reduced-diameter neck 27 situated in yoke opening13B, the cover plate 13A is replaced and secured. While this ball andsocket mounting permits a swivel action of the hanger assembly, the webor protrusion 27 permits only a few degrees of relative rotation. Thus,since the outlet box is rigid, the housing 20 is not free to rotateappreciably around its axis of symmetry 29. Similarly, washer 22 iskeyed to housing 20 by means of the interlocking projection and slot 31,and stem piece 23 is keyed to washer 22 by means of the proximity offlats 4l on the stem piece and flats 32 on the washer. As will beappreciated, the stem piece can rotate only a very few degrees after thehanger is installed in the electrical box. As a result, there cannot besufficient rotation of the fixture or hanger to cause the electricalwires to twist or to unattractively orient the fixture.

In mounting the electrical fixture, either the length of conduit 16 orthe conduit with the fixture attached is screwed into the threads 47with the wiring extending through the central hold 52 of the stern piece23 and then through the hollow housing l5. They then exit within theelectrical outlet box 13 where they are properly attached into the powerlines.

As will be appreciated, this mounting permits the fixture to swivelfreely from side to side as well as deflect vertically. The shape of thespring not only gives it a firm base of support, but it also inherentlyachieves a simple assembly. These two advantages are intertwined withperhaps the most significant advantage, and that advantage is thatachieved by the use of a variable spring rate cushion. This variablerate permits a wider weight range of fixtures to be hung from eachhanger. In the configuration described, the hangers are less expensivethan earlier models and two basic units are sufficient to replace thefour formerly required. For example, and because of the inherentcharacteristics of a variable rate spring, the lower capacity hanger ofthe two replacing units has been designed for and is capable ofperforming a' satisfactory job in mounting fixtures ranging from 3 to l2pounds, while the larger hanger satisfactorily carries hangers rangingfrom l2 to 48 pounds. A third hanger has been introduced which iscapable of carrying loads from 48 to 120 pounds. Thus, it can be seenthat the same weight range of fixtures can be handled by half as manybasic units.

Although this description has set forth specific weight ranges in itsdesigns, these are not intended to be limiting. And, while the inventionis shown in the drawings to assist in an understanding of one preferredembodiment of the invention, this is not to defeat that purpose of apatent which is to protectively cover the inventive concepts containedtherein. The appended claims are the chief aid toward this purpose as itis these that point out the scope of the invention.

Iclaim:

1. An improved vibration-isolating mounting for a lighting fixture,comprising: a generally hollow support including a housing and having abottom surface with a hole therethrough, a compression spring carriedvertically in said housing and having a lower coil resting on saidbottom surface and an upper coil thereabove, a single-piece stem memberin said housing having an integrally formed protrusion above and of alarger transverse dimension than the diameter of said upper coil andextending over a portion thereof for bearing downwardly thereon, saidstem having central portions depending from said upper end generallyaxially thereof and through the hole in the bottom surface of thesupporting housing to a lower end below said hole, said lower end of thestem having attachment means thereon for connection to a lightingfixture assembly, said protrusion on the stem including atleast onelaterally outwardly extending ear means jutting outwardly in a generallysingular lateral direction away from said stem for effecting captivatingassembly of the spring on the stem member by screwing one onto theother.

2. The mounting as set forth in claim 1, wherein one end of saidcompression spring has a smaller inner diameter than the other end, andwherein said smaller inner diameter is less than said transversedimension of the stem member, and said other end has a larger innerdiameter than said transverse dimension of the stem member to facilitatethe rapid captivating assembly of the spring onto the stem piece.

3. For use in hanging electrical fixtures or the like, improvedvibration isolation means, comprising: a generally hollow andbell-shaped housing with a passageway extending axially therethrough andhaving swivel means generally at the top thereof for providing auniversal connection to the mating portions of an electrical outlet boxand for causing said housing to depend generally vertically therefrom,said housing opening downwardly at the bottom portions; a closure platexedly secured to the bottom portions of said housing, said plate havingan opening therein; an axially aligned compression spring of varyingdiameter and having a variable spring rate carried within said housing,said spring having a relatively large diameter lowermost portion bearingdownward against said plate around said opening; and an elongate stempiece extending axially through said conical spring and having an upperend with a pair of diametrically opposed and laterally outwardlyextending lugs having an overall lateral dimension between the maximumand minimum diameters of said spring and greater than the diameter ofthe coil immediately therebelow for resting thereon, said stem piecehaving a thinner intermediate portion extending through said closureplate opening, said stem piece having a. lower end of larger transversedimensions than portions of said closure plate opening, and said stempiece also having a lowermost portion below said plate including meansfor attaching a light fixture thereto.

Il. The vibration isolation means as set forth in claim 3, includingmeans on said stem piece and closure plate for preventing relativerotation between said lowermost portions ol the stem piece and thehousing.

5. The vibration isolation means as set forth in claim 3, wherein saidclosure plate, spring, and stem piece form a subassembly, and whereinthe hole in said closure plate is large enough to admit the upper end ofsaid stem piece therethrough.

1. An improved vibration-isolating mounting for a lighting fixture,comprising: a generally hollow support including a housing and having abottom surface with a hole therethrough, a compression spring carriedvertically in said housing and having a lower coil resting on saidbottom surface and an upper coil thereabove, a single-piece stem memberin said housing having an integrally formed protrusion above and of alarger transverse dimension than the diameter of said upper coil andextending over a portion thereof for bearing downwardly thereon, saidstem having central portions depending from said upper end generallyaxially thereof and through the hole in the bottom surface of thesupporting housing to a lower end below said hole, said lower end of thestem having attachment means thereon for connection to a lightingfixture assembly, said protrusion on the stem including at least onelaterally outwardly extending ear means jutting outwardly in a generallysingular lateral direction away from said stem for effecting captivatingassembly of the spring on the stem member by screwing one onto theother.
 2. The mounting as set forth in claim 1, wherein one end of saidcompression spring has a smaller inner diameter than the other end, andwherein said smaller inner diameter is less than said transversedimension of the stem member, and said other end has a larger innerdiameter than said transverse dimension of the stem member to facilitatethe rapid captivating assembly of the spring onto the stem piece.
 3. Foruse in hanging electrical fixtures or the like, improved vibrationisolation means, comprising: a generally hollow and bell-shaped housingwith a passageway extending axially therethrough and having swivel meansgenerally at the top thereof for providing a universal connection to themating portions of an electrical outlet box and for causing said housingto depend generally vertically therefrom, said housing openingdownwardly at the bottom portions; a closure plate fixedly secured tothe bottom portions of said housing, said plate having an openingtherein; an axially aligned compression spring of varying diameter andhaving a variable spring rate carried within said housing, said springhaving a relatively large diameter lowermost portion bearing downwardagainst said plate around said opening; and an elongate stem pieceextending axially through said conical spring and having an upper endwith a pair of diametrically opposed and laterally outwardly extendinglugs having an overall lateral dimension between the maximum and minimumdiameters of said spring and greater than the diameter of the coilimmediately therebelow for resting thereon, said stem piece having athinner intermediate portion extending through said closure plateopening, said stem piece having a lower end of larger transversedimensions than portions of said closure plate opening, and said stempiece also having a lowermost portion below said plate including meansfor attaching a light fixture thereto.
 4. The vibration isolation meansas set forth in claim 3, including means on said stem piece and closureplate for preventing relative rotation between said lowermost portionsof the stem piece and the housing.
 5. The vibration isolation means asset forth in claim 3, wherein said closure plate, spring, and stem pieceform a subassembly, and wherein the hole in said closure plate is largeenough to admit the upper end of said stem piece therethrough.